improve assert no labels found

utils/datasets.py

@@ -379,7 +379,7 @@ class LoadImagesAndLabels(Dataset):  # for training/testing
 
                 pbar.desc = 'Caching labels (%g found, %g missing, %g empty, %g duplicate, for %g images)' % (
                     nf, nm, ne, nd, n)
-            assert nf > 0, 'No labels found. See %s' % help_url
+            assert nf > 0, 'No labels found in %s. See %s' % (os.path.dirname(file) + os.sep, help_url)
 
         # Cache images into memory for faster training (WARNING: large datasets may exceed system RAM)
         if cache_images:  # if training